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1d42460a49
Currently ccu_frac_helper_set_rate() doesn't wait for a lock bit to be
set before returning. Because of that, unstable clock may be used.
Add a wait for lock in the helper function.
Fixes: 89a3dfb787 ("clk: sunxi-ng: Add fractional lib")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
113 lines
2.8 KiB
C
113 lines
2.8 KiB
C
/*
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* Copyright (C) 2016 Maxime Ripard
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*/
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#include <linux/clk-provider.h>
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#include <linux/spinlock.h>
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#include "ccu_frac.h"
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bool ccu_frac_helper_is_enabled(struct ccu_common *common,
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struct ccu_frac_internal *cf)
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{
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return false;
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return !(readl(common->base + common->reg) & cf->enable);
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}
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void ccu_frac_helper_enable(struct ccu_common *common,
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struct ccu_frac_internal *cf)
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{
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unsigned long flags;
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u32 reg;
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return;
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spin_lock_irqsave(common->lock, flags);
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reg = readl(common->base + common->reg);
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writel(reg & ~cf->enable, common->base + common->reg);
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spin_unlock_irqrestore(common->lock, flags);
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}
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void ccu_frac_helper_disable(struct ccu_common *common,
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struct ccu_frac_internal *cf)
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{
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unsigned long flags;
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u32 reg;
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return;
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spin_lock_irqsave(common->lock, flags);
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reg = readl(common->base + common->reg);
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writel(reg | cf->enable, common->base + common->reg);
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spin_unlock_irqrestore(common->lock, flags);
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}
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bool ccu_frac_helper_has_rate(struct ccu_common *common,
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struct ccu_frac_internal *cf,
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unsigned long rate)
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{
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return false;
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return (cf->rates[0] == rate) || (cf->rates[1] == rate);
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}
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unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
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struct ccu_frac_internal *cf)
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{
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u32 reg;
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pr_debug("%s: Read fractional\n", clk_hw_get_name(&common->hw));
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return 0;
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pr_debug("%s: clock is fractional (rates %lu and %lu)\n",
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clk_hw_get_name(&common->hw), cf->rates[0], cf->rates[1]);
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reg = readl(common->base + common->reg);
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pr_debug("%s: clock reg is 0x%x (select is 0x%x)\n",
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clk_hw_get_name(&common->hw), reg, cf->select);
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return (reg & cf->select) ? cf->rates[1] : cf->rates[0];
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}
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int ccu_frac_helper_set_rate(struct ccu_common *common,
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struct ccu_frac_internal *cf,
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unsigned long rate, u32 lock)
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{
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unsigned long flags;
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u32 reg, sel;
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return -EINVAL;
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if (cf->rates[0] == rate)
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sel = 0;
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else if (cf->rates[1] == rate)
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sel = cf->select;
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else
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return -EINVAL;
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spin_lock_irqsave(common->lock, flags);
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reg = readl(common->base + common->reg);
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reg &= ~cf->select;
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writel(reg | sel, common->base + common->reg);
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spin_unlock_irqrestore(common->lock, flags);
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ccu_helper_wait_for_lock(common, lock);
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return 0;
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}
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